Centrifugal device for electric motors



Oct. 11, 1932. c. H. KINDL CENTRIFUGAL DEVICE FOR ELECTRIC MOTORS Filed Feb. 13, 1932 Patented Oct. 11, 1932 UNITED STATES PATENT OFFICE CARL H. KINDL, OF DAYTON, OHIO, ASSIGNOR TO DELCO PRODUCTS CORPORATION, OF DAYTON, OHIO, A CORPORATION OF DELAWARE I CENTRIFUGAL DEVICE FOR ELECTRIC MOTORS Application filed February 13, 1932. Serial No. 592,673.

This invention relates to centrifugal switches, and particularly to switches for alternating current motors of the repulsioninduction type.

c It is-one of the obj ects of the invention to 'provide a centrifugal device for operating switch members, said device being rugged and durable in construction and noiseless in operation.

Further objects and-advantages of the present inventionwill be apparent from the following description, reference being had to the accompanying drawing, wherein a preferred embodiment of one form of the present invention is clearly shown.

In the drawing:

Fig. 1 is a longitudinal sectional View of a motor provided with a form of centrifugal switch embodying the present invention.

Figs. 2 and 3 are sectional views taken respectively on the lines 2-2 and 33 of Fig. 1.

Fig. 4 is a sectional view taken on the line 4-4 of Fig. 2.

Fig. 5 is a View looking in the direction of the arrow 5 of Fig. 4.

Fig. 6 is a sectional view on the line 6-6 of Fig. 2.

Referring to the drawing, designates a field frame carrying field windings 21 and secured to end frames 22 and 23 carrying bearings 24 and 25 respectively for rotatably supporting an armature shaft 26 carrying a rotor core 27 which receives the armature conductors 28, the leads of which are connected with an annularrow of commutator segments 29 having a plane brush engaging surface.

The commutator 29 is engaged by brushes 30, each slidably supported by holder 31 of the box-type extending from a hub 32 which is longitudinal and slidable upon a sleeve 33 integral with the end frame 22. The hub 32 carries radially extending studs 34 each of which receives the coiled intermedite portion of a spring 35. The ends 36 and 37 of each spring bear against a pair of adjacent brushes 30, which are joined together by flexible short circuiting connections 38. 50 The brush holder hub 32 is prevented from ward the comutator 29 by a spring bearing at one end against a washer 46 which is retained by the C-washer 47 received by groove 48 of the shaft 26 and retained by a cupped washer 49. The spring 45 bears against the flange 50 of a sleeve 51 having av flange 52 bearing against a flange 53 provided by the brush holder hub 32. Thus the spring 45 yieldingly urges the brushes 30 against the commutator segments 29.

The commutator segments 29 are embedded in molding material attached to a sleeve 61 having a hub 62 connected with the shaft 26. The shaft 26 supports for sliding movement a sleeve 63 against which the sleve 51 bears. The sleeve 63 is provided with an annular groove 63a for receiving an annular band made of a plurality of dumb-bell shaped copper pieces 64, strung on a wire 65 passing through an eye of each dumb-bell end. As the speed of the shaft 26 increases the band of the dumb-bell members 64 flies outwardly against the inner side of the rim of the sleeve 61 which is flush with the inner ends of the commutator segments 29, but is insulated therefrom.

The present invention provides an improved ccntrifugal device for shifting the sleeve 63 endwise in order that the dumbbell shaped members 64 may operate to short circuit the commutator segments 29 and in order that the brush holders may be moved toward the left to disengage the brushes 30 from the commutator segments. This improved centrifugal device comprisesa hub fixed to the shaft 26 and carrying diametrically opposite laterally extending pins 71 and 72 which provide journals for bell crank levers 7 3 and 77. The lever 73 has an arm 74 journaled on pin 71, and an arm 75 journaled on pin 72 and a connecting yoke 76.

The lever 77 has an arm 78 pivoted on pin 71 and an arm 79 pivoted on pin 72 and a connecting yoke 80. The yokes 76 and 80 provide sockets 82 and 84 respectively for receiving rods 86 and 88 respectively which pass through holes 90 and 92 respectively provided in the core 27 and which engage the sleeve 63. The bell-crank levers 7 3 and 77 are provided with arms 81 and 83 respectively which extend somewhat longitudinally with respect to the shaft 26 and which are parallel to each other. These arms 81 and 83 are received respectively by 'slots 85 and 87 provided in weights 89 and 91 pivoted respectively upon studs 93 and 95 carried by the flange 96 of a cup-shaped member 94 attached to the collar 70. The flange 96 is provided with an annular row of holes 97 in which lead plugs may be inserted for balancing the armature. In order toprovide for quiet operation of the centrifugal device each weight is provided with a slot 100 which receives a felt washer 101 retained by stud 102 secured to the flange 96 and retaining a dished washer 103 into which a portion of the felt washer 101 extends and which has a flange 104 bearing loosely upon the weight 89 or 91.

Normally the weights are located in innermost position toward the shaft as shown in Fig. 1 with the act-ion of the spring 45; and the commutator short circuiting device 63 is not in engagement with the commutator segments, but the brushes 30 are in engagement therewith. Therefore, the machine operates as a repulsion motor until a certain speed is obtained. As the motor speed increases the weights 89 and 91 move outwardly thereby causing the bell-crank levers 73 and 77 to rotate counterclockwise and clockwise respectively as viewed in Fig. 1, thereby causing the rods 86 and 88 to move toward the left in order to move the commutator short circuiting band 64 into engagement with the commutator segments and to disengage the brushes therefrom. Likewise, when the motor current is turned ofl' and the motor speed allowed to decrease the weights'89 and 91.are caused to move inwardly due to the action of the spring 45.. The movement of each weight is limited by an end wall of the notch 100 striking the felt washer 101. As the weights arrive at their limits of the movement in either direction no noise is heard since the weights each strike a felt comprising, in combination, an armature shaft, a collar attached to the shaft, diametrically opposite pivots provided by the collar, bell crank levers pivoted upon said pivots, and located upon opposite sides of said collar, each bell crank lever having a yoke and another arm extending from the yoke and pivoted upon the collar, rods operated by the yokes, a member to be controlled operated by the rods, a cup-shaped member having an internal flange attached to the collar and having an external flange providing a plane annular surf-ace, flat weights each pivoted upon said plane flange, and each providing a part receiving an arm of a bell crank lever, and spring means resist-ing outward movement of said weights.

2. A centrifugal device according to claim 1 further characterized as having fibrous members each for limiting movement of a weight in either direction.

3. A centrifugal device according to claim 1 further characterized as having fiber washers each received by a slot in a wei ht, studs each passin through a washer an secured to the cup-shaped member, and dished metal washers each retained by a stud and partly enclosing a fiber washer and bearing loosely against a weight. I

In testimony whereof I hereto afiix my signature. I

CARL H. KINDL. 

